# crossbeam-rs/crossbeam

Tools for concurrent programming in Rust

Repository: https://github.com/crossbeam-rs/crossbeam
Canonical: https://ross.abutalabs.com/products/crossbeam
Language: Rust
License: Apache-2.0
License Family: permissive
Topics: synchronization, concurrency, parallelism, threads, lock-free, data-structures, rust
Last push: 2026-08-11T10:11:15+00:00

## Health v2 (maintenance only)
Score: 96/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 97, release rhythm 92, longevity 100
- inputs: {"age_days": 4130, "days_push": 22, "days_rel": 58, "gap_med": 0.0, "n_releases_24m": 11}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 8558, forks 573 (observed 2026-08-28T04:10:23.509275+00:00)

## What it is
Crossbeam is a Rust library providing tools for concurrent programming, including lock-free data structures, MPMC channels, epoch-based garbage collection, and scoped thread spawning. It is widely used as a foundation for building task schedulers and parallel systems in Rust.

## Use cases
- pass messages between threads with mpmc channels
- build a work-stealing task scheduler
- spawn threads that borrow stack variables
- implement lock-free queues in rust
- synchronize thread start and end with wait groups
- avoid false sharing with cache line padding

## When to choose
- you need battle-tested concurrent data structures or channels in Rust
- you want scoped threads that can borrow local variables safely
- you are building a scheduler or parallel runtime needing work-stealing deques

## When to avoid
- you only need simple async concurrency, where tokio or std futures may suffice
- you need distributed or cross-process communication rather than in-process threading
- you want a batteries-included async runtime rather than low-level synchronization primitives

## Facets
- artifact type: library
- maturity: stable
- function: concurrency, developer-tools
- domain: developer-tools, performance
- platform: rust, cross-platform
- tags: lock-free, channels, work-stealing, epoch-gc, synchronization, threads, no-std, algorithms

## Member repositories
- crossbeam-rs/crossbeam (main) score 96

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:10:23.509275+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-29T17:26:18.183112+00:00, confidence not recorded.
  - readme: https://github.com/crossbeam-rs/crossbeam (fetched 2026-08-28T04:10:23.509275+00:00, sha b2e0e9492c64)
  - registry_crates: https://crates.io/api/v1/crates/crossbeam (fetched 2026-08-29T08:26:34.469670+00:00, sha fb6e4dd3a1d4)
- Data as of 2026-08-30T08:39:29.467469+00:00.